Tourniquet devices are commonly used in emergency medicine to stop blood flow to and bleeding from an injured limb. Tourniquets employ a length of cordage tightened around a limb to stop blood flow and allow clotting to occur. After a tourniquet is applied long enough to allow blood clotting or to stabilize the injury, in some cases the tourniquet can be slowly and partially released to prevent damage to the injured limb. It is important for tourniquets to maintain tension reliably; a sudden accidental release of tourniquet tension can result in significant loss of blood and renewed bleeding.
Sometimes it is necessary for an injured person to apply a tourniquet to himself. An injured person losing blood is weak and will be unable to apply a large force. Additionally, a person applying a tourniquet to himself typically will not have favorable leverage to apply force. Therefore, it is important in this case for the tourniquet to be settable with one hand and with a small amount of applied force. Also, the tourniquet should be able to be controllably loosened without unintentionally releasing the tourniquet pressure completely.
Tourniquets are essential in emergency medicine and are standard equipment for military and emergency medical personnel. Tourniquets sometimes need to be carried to remote areas and used in dirty outdoor conditions. For this reason, tourniquets should be small, durable, lightweight and reliable.
U.S. Pat. No. 4,125,115 to Mayo et al. describes a tourniquet employing a semi-elastic belt clamped between a jamming edge and a roller. The tourniquet of Mayo et al. does not provide a mechanism for locking tourniquet tension so that the tourniquet cannot be accidentally released. Mayo et al. has release mechanisms that can be easily triggered accidentally, resulting in sudden and complete loss of tourniquet tension. This is dangerous to injury victims, because sudden loss of the tourniquet can result in significant additional loss of blood.
It would be an advance in the art of emergency medicine and tourniquet design to provide a tourniquet that is reliably lockable and not prone to accidental release. It would also be beneficial to provide a tourniquet that can completely stop blood flow with a relatively small amount of applied force, so that an isolated single injured person can apply the tourniquet to himself.